When he's not working with A-lister clients like Lady Gaga, Ariana Grande, and Shay Mitchell, celebrity trainer Harley Pasternak is known for keeping it real on his Instagram account with healthy living tidbits, workout tips, and quickie nutrition breakdowns. So it's not just his celeb clients who benefit from his motivational musings. Now, in a new Instagram post, he's challenging his followers to pay it forward by being someone else's accountability buddy for the next month (or asking for one of your own).

You've probably heard of accountability buddies before, and it's not necessarily the same as a workout buddy. "It's someone to motivate you, someone to educate you, and someone to inspire you," Pasternak tells SELF. If you're someone who likes to try to work out and eat healthy, you just might be the motivation someone close to you is looking for. Of course, as well-intentioned as it is, being an accountability partner can also be ambiguous, so Pasternak laid out some specific guidelines.

"Commit to going on at least one walk with them this week, eating at least one meal with them this week, and taking them to the gym or working out with them at least once this week," he wrote in his Instagram post. "On top of that, you're going to have them email you every night before they go to bed, and tell you how many steps they took that day, what they ate that day, and how many hours they slept."

Admittedly, it's not an entirely altruistic move to be someone else's accountability buddy. "As a byproduct of this, you will be more aware of the healthy habits that you need to do in your life," writes Pasternak. Win-win.

On the flip side, if you're having a hard time sticking to your health goals, you can also use his guidelines to ask someone else if they'd be down to be your accountability partner.

"When you are accountable to someone else, you're also being accountable to yourself," Pasternak tells SELF. "The act of typing out how many steps you took today, where you were, and how much you slept is in and of itself one of the most important things that you can do. Then pressing send on that email symbolizes your dedication to your process and results."

And if emailing sounds like too much of a chore, you can type it all out in a nightly text, or even send Snapchat updates throughout the day to your buddy—whatever gets you going.

When you're deciding who to ask to be your accountability partner, think about the people who are always cheering on your efforts as they do their best to stick with their own healthy habits, too. "Choose an accountability partner that cares about your well-being, but you're not too close to. A husband or wife may not be the best idea, but a friend or coworker may be a good idea," suggests Pasternak. "Someone that leads by example, and would never have you do anything extreme, radical, or short-lived...a good accountability partner will respond with constructive criticism that helps you rather than deflates your confidence." (They're supposed to be an encouraging, helpful voice, not a drill sergeant.)

An accountability partner set-up doesn't have to be a one-way street, either. If you have that one friend that you always talk about getting in shape with, hold each other to your goals together—just make sure they're as committed to learning and growing in their fitness journey as you are.